Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating activities
Net income (loss)	$ (8,927)	$ 21,758
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Deferred income tax provision (benefit)	(2,917)	7,624
Depreciation and amortization	38,983	41,036
(Gains) losses on sale of equipment	(5,337)	4,551
Share based compensation	2,965	3,791
Other	(926)	381
Unrealized loss (gain) on equity investment	10,120	(20,191)
Changes in operating assets and liabilities:
Receivables	(17,502)	(27,163)
Prepaid insurance and licenses	2,283	4,580
Operating supplies	(993)	(724)
Other assets	(4,789)	(1,967)
Accounts payable and other accrued liabilities	2,025	5,954
Accrued wages and benefits	5,807	771
Net cash provided by operating activities	20,792	40,401
Investing activities
Payments for purchases of property and equipment	(94,448)	(62,851)
Proceeds from sales of property and equipment	27,527	47,660
Net cash used in investing activities	(66,921)	(15,191)
Financing activities
Borrowings under lines of credit	262,100	138,812
Payments under lines of credit	(216,800)	(123,812)
Borrowings under long-term debt	44,514	38,116
Payments of long-term debt and finance leases	(44,191)	(83,961)
Payments of financing costs		(100)
Tax withholding related to net share settlement of restricted stock awards	(431)	(1,211)
Proceeds from issuance of common stock under ESPP	725	538
Proceeds from long-term consideration for sale of subsidiary	320	305
Book overdraft	(2,658)	5,873
Net cash provided by (used in) financing activities	43,579	(25,440)
Net change in cash and cash equivalents	(2,550)	(230)
Cash and cash equivalents
Beginning of year	5,695	5,505
End of period	3,145	5,275
Supplemental disclosure of cash flow information
Cash paid during the year for interest	8,175	6,956
Cash paid during the year for income taxes	839	720
Supplemental disclosure of significant noncash investing and financing activities
Uncollected proceeds from asset sales	643
Property and equipment amounts accrued in accounts payable	1,767	2,901
Finance lease additions	$ 536	$ 5,572